Valving assembly for hydraulic shock absorbers



Nov. 30, 1937- R. F. PEO ET AL 2,100,407

I VALVING ASSEMBLY FOR HYDRAULIC SHOCK ABSORBERS Filed Feb. 8, 1956 3 Sheets-Sheet 1 47 /i v 4a A I 5 Y /31 H 5W 5471- 5 4 Eavk 7. Pea.

Nov. 30, 1937. R. F. PEO ET AL 2,100,407 I VALVING ASSEMBLY FOR HYDRAULIC SHOCK ABSORBERS Filed Feb. 8, 1936 n 3 Sheets-Sheet 5 121 12a 124 14 122 E 120 I 32 1 115 124 1 7. Y 32 135 33 4 152 ZVEEYUFE 136 1 134 10 E4405 1 P60.

Farm: W2.77 a rum. I

Patented Nov. 30, 1937 i VALVING ASSEMBLY FOR HYDRAULIC SHOCK ABSORBERS Ralph F. Peo, Carl F. Lautz, and Gervase M. Magrum, Buffalo, N. Y., assignors to Houde Engineering Corporation, Buffalo, .N. Y., a corporation of New York Application February 8, 1936, Serial No. 62,943

8 Claims. (Cl. 188-100) wall 3-is closed by a cover structure 8 whichmay. 5 vide a valving assembly in which an axially movbe secured by threaded engagement with the able valve plug cooperates with a metering orifice wall 3. i a for metering of the fluid flow during rebound Within the ring 4 is the cylindrical piston hub operation of the vehicle spring, with the 'valve 9 which extends between the' abutment partil\) plug normally held by a spring for metering of tions 5 and 6 and which has piston vanes I9 and 10 the fiuid flow under normal pressure conditions. I l. extending therefrom ,for bearing engagement but with the spring yielding for movement of with the ring, this piston structure together with the valve plug for increased orifice opening, tothepartitionmcmbers dividing the space within gether'with means for adjusting the spring tenthe ring and between the base and cover struc- 5 sion from the exterior of the shock absorber. ture 8 into high pressure chambers l2 and 12' 15 ,A further object of the invention is to provide and low pressure chambers l3 and I3 from a r in close association with the rebound flow conwhich the oil is displaced as the piston structure trolling valve, a second valve, preferably of the oscillates. j V disc type, forcontrolling the fluid flow during A shaft l4 extends from the piston hub 9 and 29 compression movement of the vehicle spring, at its outer end is journalled in the cover strucwith such second valve normally held in passage tureB in a well known manner, the shaft at its closing position by a spring and the fluid presouter end having applied thereto a lever l5 (Fig. sure and with the valve unseated by fluid pres- 2) for connection usually with the axle of the sure against the resistance of' the spring during vehicle sothat duringrelative movement between V compression movement of the vehicle spring. the chassis and axle the piston structure will Another object of the invention is to provide be oscillated for displacement of the hydraulic an arrangement in which the rebound or high fluid. r I pressure fiow controlling valve assembly may be Referring to Figure '2, the shaft I4 has the axwithdrawn as a unitary assembly from the shock ial bore I6 extending therethrough which comabsorber for replacement thereof by another municates at its innerend with-the counterbore 3O valving assembly of different characteristics. ll in the hub9, the hub having the intermediate A further important object is to make the bore-I8 of larger diameter and an end bore l9 movable valve elements light and so cooperable of still larger diameter, the bore I9 receiving the with their seats as to prevent noisy operation bearing lugv 20 extending from the base I for S5 and to avoid pressure surges upon opening of journalling the piston structure at its inner end.

the passageways controlled by these valves. Seated in the bottom of the intermediate bore l8 The above enumerated and other important is an orifice plate 2! having the passage or orifice features of the invention are embodied in the 22 therethroughwhose surrounding edge is comstructure disclosed on the drawings, in which paratively sharp. On its inner side this orifice drawings: plate has the concentric annular seating ridges 40 Figure 1 is a plan View of a hydraulic shock 23 and 24 for the valve disc 25 which hasa cenabsorber in which we have shown our valving tral passageway in alignment with the orifice assemblies applied, part of the shock absorber passageway 22. An abutment plug 21 threads cover being removed; into the end of the intermediate bore 18 and af- Figure 2 is a section on plane IIII of Figure fords an abutment seat for one'end of the spring 1, showing one form of valving assembly for the 28 which at its other end abuts the valve disc shock absorber; 25 and tends to hold the valve disc against its Figures 3, 4; and 5 show modified valving asseats 23 and 24. A bushing'ZS is interposed be- Semblies; tween the plug 2'! and the orifice plate 2| so Figure 6 is a section on plane VI-VI of Figure that this orifice plate is securely held clamped 5; and in the bottom of the bore I8. 7 a

Figure '7 shows another modified valving ar- The plug, the bushing 29, and the orifice plate rangement. 2| form a valve chamber 30 for the valve disc The shock absorber to which we have shown and this chamber is connected by the passage 3| 53 the valving assembly applied is of the so-called in the plug with the chamber or bore [9 which '55 rotary type. Briefly describing the structure, it is connected by passages 32 and 3 2 with the comprises a base i having ears 2 for securing it high pressure hydraulic working chambers l2' to a support as for example the chassis of an auand I2 of the shock absorber. The orifice plate tomobile. The annular wall 3 extends from the 2| has ports 33 therethrough between the seating 63 base and within this wall is the ring 4 from (so This invention relates to a valving assembly adapted particularly for controlling the hydraulic fluid flow in shock absorbers applied to automotive vehicles. 7

An important object of the invention is to prowhich extends the abutment partitions 5 and 6, this ringstructure being secured by pins I extending through the abutment partitions and i into the base I. The outer end of the annular ridges 23 and 24, these 'ports connecting the bore or valve chamber H with the valve chamber 30 when the valve disc 25 is unseated.

Within the shaft bore i is the valving assembly for controlling the flow through the orifice passage 22 from the valve chamber l? to the valve chamber 35. The valve assembly comprises a cylindrical sleeve 34 having secured in its inner end a guide head 35 having the cylindrical bore 36 for the body 31 of the valve V. The valve guide head 35 has the counterbore 33 at its inner end through which extend the neck 35 and the cylindrical plug end 46 of the valve, the plug end 45 projecting through the orifice 42 in the plate 2|.

The sleeve 34 is secured at its outer end to a head 4| which has threaded engagement with the threaded end of the shaft bore |6. As shown, the heads 35 and 4| may be secured to the sleeve 34 by being press fitted into the ends thereof. When assembly is made, the threaded head 4| is screwed into the shaft bore until the end of the head 35 abuts the orifice plate 2|, the head 35 having the passageway 42 connecting its bore 38 with the valve chamber this valve chamber being connected by passages 43 and 43 with the low pressure working chambers I3 and I3 of the shock absorber.

The valve V has at its outer end a flange 44 which is within the sleeve 34 and normally held against the inner end of the head 35 by a spring 45 within the sleeve, the spring being abutted at its outer end by a washer 46 engaged by a screw 4'! threading through the outer sleeve head 4|, the screw extending to the exterior of the shaft bore through a gland 48 having threaded engagement in the outer end of the bore, the screw having a head 49 whereby it may be readily turned. By turning of this screw the pressure of the spring 45 against the valve V may be adjusted and the spring pressure tends to hold the valve in normal position with its plug end 40 within the orifice passage 22. The diameter of the valve end is somewhat less than the diameter of the orifice passage 22 in order to leave a normal passageway which is always open to fluid flow. At its ends, the valve plug is tapered or cut away on the bias as indicated at 56 so that when the valve is shifted inwardly the biased end communicates with the orifice passageway 22 for providing additional passageway for fluid flow,

Describing the operation, the various parts are normally in the position shown in Figure 2. Duringrebound movements of the vehicle spring with which the shock absorber is associated, the displaced hydraulic fiuid flow will be from the high pressure working chambers I2 and I2 thru the passages 32 and 32 and into valve chamber 30, the pressure of the fluid against the valve disc 25 cooperating with the pressure of the spring 23 to hold the valve disc seated for closure of the passages 33. All of the fluid flow therefore, has to be through the orifice passage 22 and through the passages 43 and 43 to the low pressure hydraulic working chambers. Under normal pressure conditions the valve V will be held by the spring 45 in its normal outer position, but under abnormal pressure conditions the pressure against the valve will shift it inwardly to overcome the spring resistance and to move the biased end 53 of the valve into the orifice passage 22 for increasing the size of the passageway for fluid flow, and such increased passage remains until normal pressure conditions are restored and the valve is again returned to normal position.

During compression movements of the vehicle spring the fluid will flow from the low pressure working chambers |3 and I3"through'the passages 43 and 43, and if the displaced fluid volume is too great, the orifice passage 22 will not be large enough to accommodate the flow and the pressure acting through the ports 33 against the valve disc 25 will unseat the valve for opening of the ports and for correspondingly increased fluid passageway, the fluid flowing through the passages 32 and 32 to the high pressure working chamber.

The valve disc 25 is made light and the seat rings 23 and 24 are so narrow edged that the area increment subject to pressure, as the valve opens, remains nearly constant, thus avoiding pressure surge when the valve opens. This arrangement also eliminates noise,

It will be noted that after the gland 48 has been withdrawn from the shaft bore, the entire rebound flow control valve assembly may be withdrawn as a unitary structure from the shaft bore by screwing out the head 4| from the bore. Replacement of a withdrawn valve assembly by another of diiTerent control characteristics may therefore readily be accomplished.

To limit the outward movement of the valve V by the fluid pressure, a stop shoulder 5| is provided on the sleeve 34 for engagement by the valve flange 44, and another shoulder 52 on the sleeve limits the inward movement of the washer 46 and protects the spring against overcompression by the screw 41.

In the modified arrangement shown in Figure 3, a backing plate 53 is seated in the bottom of the intermediate bore l8 and between this backing plate and the bushing 54 is clamped the orifice plate 55, the plug 56 threading into the end of the bore l8 engaging the bushing to clamp the various parts together. The orifice plate 55 has the outer and inner seating ridges 51 and 58 for the valve disc 59 which is normally held against the seat by the spring 6|], the valve disc having the axial passageway 6| therethrough.

The orifice plate 55 has the orifice passage 62 in alignment with the valve disc passage 6| and the orifice plate has also the ports 63 therethrough communicating with the annular space between the seat ridges 51 and 58, and the annular chamber 64 in the backing plate 53, the backing plate having ports 65 therethrough communicating with the valve chamber I! which is connected by passages 43 and 43' with the low pressure working chambers l3 and I3 of the shock absorber, the valve chamber 30 for the valve disc 59 being connected by passages 32 and 32 with the high pressure working chambers of the shock absorber.

The valve V is supported by the sleeve 66 in the shaft bore Hi, the end of the sleeve having the bore 61 for the valve body whose flange 68 normally abuts against the inner side of the sleeve end. The biased cylindrical valve end 69 extends within the orifice passage 62 and is of less diameter than that of the orifice in order to leave a' normal size orifice passage for the flow of the fluid during normal pressure conditions. The sleeve 66 at its outer end is secured to the plug which has threaded connection in the end of the shaft bore IS. A stem H has the screw thread connection 12 with the threaded bore of the plug and abuts a washer I3 which engages the outer end of the spring 74 which at its inner end abuts the valve flange 68 and tends to hold the valve structure in'normal position. A bushing I5 lines the sleeve 66 and is secured by the sleeve to the plug I0, the bushing at its inner end forming a stop for limiting the outward movement of the valve structure V. The screw plug I is screwed in until the inner end of the sleeve 66 abuts the annular flange I6 extending outwardly from the backing plate 53, this sleeve having'one or more ports I1 therethrough for connecting the interior thereof with the valve chamber I1. The screw stem 'II extends through a packing plug or gland I8 threading into the outer end of the shaft bore, to efiect a seal against the escape of fluid from the shaft bore.

During rebound movement of the vehicle spring the displaced hydraulic fluid flows from the high pressure working chambers I2 and I2 through the passages 32 and 32 and into the valve chamber 30, the fluid pressure together with the pressure of the spring 60 holding the valve 59 seated so that all the fiuid flow must be through the orifice passage 62, the fluid flowing into the interior of the extension E6 on the backing plate 53 and from there through ports I1 into chamber I! and then through passages 43 and 53 to the low pressure working chambers I3 and i3 in the shock absorber. Under abnormal pressure conditions the spring 14 will yield so that the pressure may shift the valve V outwardly to expose its biased end to the orifice passage 62 for increasing the size of the passage for increased flow for 'relieving the excess pressure.

During compression movement of the vehicle spring the fluid displaced from the low pressure working chambers I3 and I3 flows through passages 43 and 43 into the chamber I1 and through ports 65 and 53 against the valve disc 59, the pressure overcoming the resistance of the spring 60 so that the valve disc is unseated to provide a low resistance path for fluid flow in addition to the path through the restricted orifice 62, the fluid flowing from the valve chamber 30 through passages 32 and 32 to the high pressure working chambers I2 and I2.

In Figure 4 the valving arrangement is slightly modified over the arrangement shown in Fi ure 2. The orifice plate 88 is at the bottom of the intermediate bore 1 8 and is held in place by a bushing 8! whose outer end is engaged by a plate 82 which is secured as by deflecting over against the back thereof the metal at the outer corner of the bore i3, as indicated at 83. The orifice plate 80 has the outer and inner annular seat ridges 84 and 85 against which the valve disc 86 is normally held seated by the spring 81. The valve disc has the axial passageway 88 therethrough aligned with the orifice passages 89 in the orifice plate, the orifice plate having ports 90 between the seating ridges and communicating with the chamber I'I, these ports being closed when the valve disc is seated.

The supporting structure for the valve V comprises a sleeve SI having the head 92 whose bore 93 receives the valve V, the flange 94 at the inner end of the valve normally abutting against the inner side of the sleeve head 92. The neck 95 of the valve terminates in the biased cylindrical plug end 96 which engages in the orifice passage 89.

At its outer end the sleeve 9| is secured to a screw plug 91 having threaded engagement in the outer end of the shaft bore I 6, the sleeve having the bushing 98 forming a stop for limiting the outward movement of the valve V. The plug 91 is screwed into the shaft bore until the end of at the shaft bore I6 and abuts against the orifice: plate, the sleeve having the bore H6 in which the sleeve end having the port 99 connecting the.

bore 93 with the chamber IL The screw plug 91 has the axial bore I00 for slidably receiving a pin IOI, this pin abutting at its inner end against a washer I02 which forms the abutment for the outer end of the spring I03 which at its inner end engages against the valve flange 94. The outer end of the pin IOI is abutted by the closure plug i 04 threading into the outer end of the shaft bore to close the bore, packing I being interposed between the end of the shaft and the abutment flange I06 on the plug. With this arrangement, if it is desired to increase or decrease the spring, tension against the valve V, the plug I04 can be removed and a longer or shorter pin IOI introduced. If greater spring ten-- sion is desired a longer pin is inserted and if less tension is desired a shorter pin is inserted, and when the plug I 54 is screwed into position, the

pin isshifted against the washer I02 and the spring E63 is tensioned to a to the length of the pin.

The operation of the assembly shown in Figure degree corresponding 4 is substantially the same as in the preceding as 'semblies, abnormal pressure during rebound operation of the vehicle spring causing the valve V to be shifted against the spring resistance for I moving the biased end of the valve in the orifice passage for increased fluid passageway until normal pressure conditions are restored. During compression movement of the vehicle spring the.

valve disc is unseated to provide a lower resistance path for the flow low pressure chambers to the high pressure chambers of the shock absorber.

In the modified structure shown in Figure 5 we have substantially the same valve structure and arrangement as that shown in'Figure 2, the orifice plate I01 being at the bottom of the bore l3 and provided with ports I08 communicating with the chamber H which is connected by passages 43 and 43 with the low pressure working chambers I 3 and I3 of the shock absorber. A plug I09having threaded engagement in the bore I8 holds the orifice plate in position, and the spring H9 within the plug holds the valve disc HI normally seated against the orifice plate to close passageway through the ports I08, the valve disc having the annular channel I I2 in communication with the ports. orifice passage II 3 into end N4 of the valve V.

The valve Vis supported by the sleeve I I5 which its inner end has threaded engagement with which extends the biased extending from the head I I9, the sleeve being secured to the lug as by means of a pin I20. The head I 59 has the screw driver slot I 2i whereby the sleeve may readily be screwed into normal position of abutment against the orifice plate I07.

The sleeve II5 has opposite longitudinally extending guide slots radial arms I23 on an abutment washer I24 which is slidable within the sleeve and forms the outer abutment for the spring I25 which at its inner end engages the flange I26 of the valve V.

Within the shaft bore I6 is the bushing I21 which surrounds the outer end of the sleeve and of the fluid from the The orifice plate has the I22 through which extend the the lug head i it, the bushing abutting at its inner end against the arms l23 of the abutment washer i2 3. Threading into the end of the shaft bore outside of the bushing IZ'i'is the annular nut I28 having screw thread engagement with the shaft bore for abutting against the outer end of the bushing l2? so that by turning of the nut I28 the abutment washer Q24 may be shifted for setting the tension of the spring 525. The nut has the screw driver slot 52% whereby it may be readily turned. A closure plug I3% is provided for the outer end of the shaft bore and packing I3I seals the shaft bore against leakage of fluid to the exterior thereof. A stop pin I32 is securedto and extends from the lug H8 and serves to limit the outward movement of the valve V by fluid pressure.

The operation of the structure of Figure 5 is substantially the same as that for the preceding valving assemblies, the fluid flow during rebound movement of the vehicle spring being from the high pressure working chambers through the passages 32 and 32 and through the plug I59 and from there through the orifice passage IE3 and through passages 43 and G3 to the low pressure working chambers I3 and I3 of the shock absorber. Under abnormal pressure conditions the valve V will be shifted outwardly against the resistance or" the spring I25 to bring the biased end of the valve into the orifice passage to thereby increase the size of this passage for increased flow area and relief of the excess pressure. During compression movement of the vehicle spring fluid flows from the low pressure working chambers i3 and it through the passages 13 and 43' and against the valve disc III, the pressure unseating the disc so that the fluid may flow through the ports lot and through passages 32 and 32' to the high pressure working chambers of the shock absorber.

In the modified arrangement shown in Figure 7 the orifice plate 533 is clamped between the back plate IM and the plug I35, the spring I36 within the plug holding the valve disc IS'I normally seated against the orifice plate to shut off the passage through the ports I38 in the orifice plate and the ports I39 in the back plate i3 3.

The backing plate I34 has the tubular extension I48 projecting into the shaft bore l6 and housing at its inner end the valve V, the extension having the ports E li connecting the interior thereof with the chamber H.

The orifice plate 33 has the orifice passage i 32 into which projects the biased end I43 of the valve *1 V, the valve flange I44 abutting normally against the shoulder 35 within the tubular extension I40.

Secured in the outer end of the tubular extension t le, as by means of a pin it, is the plug Ml from which extends the stop pin I58 for limiting the outward movement of the valve V. The tubular extension has the opposite slots I49 through which extend the arms Ibo of the abutment Washer 55! for the spring i52 which normally holds the valve V seated against the shoulder Hi5. A bushing I53 surrounds the outer end of the extension 5% with its inner end abutting the arms of the spring abutment washer I5I and its outer end being engageable by a nut I54 threading in the outer end of the shaft bore It so that by turning of the nut the abutment washer ilii may be moved for setting of the spring I52 to the desired tension. A closure plug IE5 is provided for the outer end of the shaft bore.

The operation of the structure of Figure 7 is substantially the same as that of the preceding structures, the fluid flow during rebound movement of the vehicle spring being solely through the orifice passage I42, which passage is increased in area upon abnormal pressure conditions when the valve V is shifted outwardly to bring the biased end thereof into the orifice passage. The low pressure flow, during compression movement of the vehicle spring, causes unseating of the valve disc I33 for reduced resistance passage flow for the fluid.

It will be noted that in the arrangement of Figure 7 the valving assembly, involving the valve V and its supporting tube extending from the backing plate I34, is a unitary assembly which is inserted into the shaft bore from the inner end thereof and then clamped in place by the plug I35. In the valving arrangements of the preceding figures the valving assembly involving the valve V is insertable into the shaft bore from the outer end thereof.

We thus produce simple and efficient valving assembly in which a valve is cooperable with an orifice passage for determining the resistance to the fluid flow during rebound movement of the vehicle spring, the valve being shiftable by excess pressure to increase the size of the orifice passage, the spring tension for resisting movement of the valve being adjustable from the exterior of the shock absorber, a check valve preferably in the form of a disc being intimately associated with the aforesaid valving structure to control the flow during compression movement of the vehicle spring.

Although we have shown various practical and efiicient embodiments of the features of our invention we do not desire to be limited to the exact construction, arrangement and operation shown and described as changes and modifications may be made without departing from the scope of the invention.

We claim as follows:

1. A valving assembly for controlling the fluid flow in a hydraulic shock absorber, comprising an orifice plate having an orifice passage therethrough, a valve plug having a tapered outer end engaging in said orifice passage to define therewith an annular orifice, said valve plug being shiftable by fluid pressure in one direction for exposing more or less of its beveled end to said orifice to thereby increase the orifice area, a guide support for said valve plug and a tension spring therein resisting axial movement of the valve plug, said orifice plate having ports therethrough independently of said orifice, a valve disc seated against said orifice plate, a spring yieldably holding said valve disc seated for closure of said ports, said valve disc being arranged to be unseated by fluid flow in the opposite direction for exposure of said ports to such flow.

2. A valving assembly for controlling the fluid flow in a hydraulic shock absorber, comprising an orifice plate having an orifice passage therethrough, a valve plug having a tapered outer end engaging in said orifice passage, to define therewith an annular orifice, said valve plug being shiftable by fluid pressure in one direction for exposing more or less of its beveled end to said orifice to thereby increase the orifice area, a guide support for said valve plug and a tension spring therein resisting axial movement of the valve plug, said orifice plate having ports therethrough independently of said orifice, a valve disc seated against said orifice plate, a spring yieldably holding said valve disc seated for closure of said ports, said valve disc being arranged to be a unseated by fluid flow in the opposite direction for exposure of said ports to such flow, and means for adjusting the tension of the first mentioned spring. a V

3. Valving assembly for controlling the fluid fiow in a hydraulic shock absorber, comprising an orifice plate having a passage therethrough, a valve plug having an end in said orifice passage and cooperating therewith to define a restricted annular orifice, said valve being arranged to be shifted axially by fluid pressure in one direction and being shaped to effect increase of the size of said orifice in accordance with increasing fluid pressure, a spring resisting axial movement of said valve, said orifice plate having a port therethrough, a check valve for seating against said orifice plate, a spring yieldably holding said check valve seated for closure of said port, said check valve being unseated by fluid flow in the opposite direction for exposure of said port to said flow.

4. A valving assembly for controlling the fluid flow in a hydraulic shock absorber, comprising an orifice member having an orifice passage therethrough, a valve plug having an end projecting into said orifice passage to partially close said passage to leave a restricted annular orifice, said valve plug being arranged for axial movement away from said orifice member by abnormal pressure of fiuid flow in one direction and the valve end being shaped to effect increase in the size of said orifice during such axial movement, a spring abutment, a spring between said abutment and said valve plug tensioned to resist axial move-' ment of said valve plug, means for shifting said spring abutment for adjustment of the spring tension, said orifice member having ports therethrough, a check valve for seating on said orifice member to control said ports, a spring resisting unseating of said check valve, the pressure of the fluid fiow in the opposite direction causing unseating of said check valve for exposure of said ports to the fluid flow.

5. A valving assembly for controlling the fiuid flow in a hydraulic shock absorber, comprising a plate having a passageway therethrough, a valve plug having an end projecting into said passage to define an annular orifice, said valveplug being adapted to be shifted axially and its end being shaped for effecting variation in the size of said orifice during said shifting, a supporting structure for said valve plug in which said valve plug is supported at one end, a'supporting head for the other end of said supporting structure, a

spring abutment movable in said supporting structure, a spring between said abutment and said valve plug for resisting axial movement of said valve plug, said supporting structure head having a bore therethrough for receiving abutment pins of various lengths, and an inserted abutment pin engaging at its inner end with said spring abutment member, and means engageable with the outer end of said pin for effecting shift thereof and of said spring abutment member for adjustment of the spring tension.

6 A valving assembly for controlling the flow of fluid in a hydraulic shock absorber, comprising an orifice member having an orifice'opening, a valve'plug having a tapered end engaging in said orifice opening to control the size thereof, a tubular supporting frame providing a guide support at its inner end for said valve plug" and having an internal shoulder, said valve plug having a flange for engagement with said shoulder, a head 1 for said tubular frame having an axialbore, a spring abutment member within said frame, a spring interposed between said abutment member and the valve plug flange foryieldably holding said valve plug in normal position for the normal size of said orifice, the fluid pressure against said valve tending to shift it against the spring resistance for increased opening of said orifice, an abutment member outside of said supporting frame head and a pin in said supporting structure head bore shiftable by said outer abutment against said spring abutment washer for movement of said spring abutment to adjust the tension of said spring, the length of said pin determining the degree of tensioning of said spring.

7, A valving assembly for controlling the fluid I flow in a hydraulic shock absorber, comprising a piston structure having a bore therethrough and' operable between high and low pressure hydraulic Working chambers and having passageways connecting said high and low pressure working chambers respectively with said bore, said valving assembly comprising an orifice member in the inner end of said bore and interposed between the high and low pressure flow passages, a supporting frame in the outer end, of said piston structure bore, said orifice plate having an orifice passage therethrough, a valve plug axially shiftable in the inner end of said supporting frame and having an end projecting into said orifice passage and shaped to vary the size of said orifice pass-age when the valve plug shifts axially, a supporting head for said supporting frame having threaded engagement in said piston structure, bore, a spring abutment member within said supporting --frame, a spring between said abutment member and the valve plug tending to hold said valve plug in position for normal size of said orifice, an abutment member having threaded engagement in the outer end of the piston structure bore, said supporting frame head having an axial passage therethrough, and a pin in said headbore passageway forengaging at its inner end with'said spring abutment member, the outer end ofsaid pin being engaged by said threaded abutment member for longitudinal shift of said pin and movement of said spring abutment member for adjusting the tension of said spring. 7

8. A valving assembly for controlling the fluid flow in a hydraulic shock absorber comprising means providing a fiuid flow passageway, a valve plug for controlling the flow through said pas sageway, a supporting structure for said valve plug in which said valve plug is axially shiftable at one end for cooperation with said passageway, a supporting head for the other end ofsaid supporting structure, a spring abutment movable in said supporting structure, a'spring between said abutment and said valve plug for resisting axial movement of said valve plug, said supporting structure head having a bore therethrough for receiving abutment pins of various lengths, an inserted abutment pin engaging at its inner end with said spring abutment member, and means engageable with the outer end of said pin for j' RALPH-F. PEOL CARL F. LAUTZ. GERVASE M. MAQRUM', 

